List the steps in the process of calculating average atomic mass given data about the isotopes of an element

1) Find out the relative abundance of each isotope. ex. Carbon 13 has around 0.01% while Carbon-12 has around 99.98%
2) Multiply each isotope by its abundance. Ex: 13(0.01) and 12(99.98)
3) add the abundances Ex. 13(0.01) + 12(99.98) = (should be around 12.01, but i just plugged in random percentages. I hope you get the point)

Tip: In a mass pectrometry graph, if it asks you for an average atomic mass of an element, 90% of the time it's going to be in the periodic table, as the mass of the element in the period table IS the average atomic mass.